Driving circuit, isolating switch circuit and power supply circuit

Abstract

The utility model relates to the technical field of electronic design, and discloses a driving circuit, an isolating switch circuit and a power supply circuit, the driving circuit comprises a control circuit and an isolating circuit, the control circuit is used for providing a control signal for the isolating circuit; the isolation circuit is used for isolating the control circuit from an external circuit by adopting an electromagnetic isolation mode, or isolating the control circuit from the external circuit by adopting the electromagnetic isolation mode and a photoelectric isolation mode; when the first control signal is changed from a low level to a high level, the isolation circuit outputs a first driving signal; when the second control signal is changed from the low level to the high level, the isolation circuit outputs a second driving signal. In the driving circuit provided by the utility model, the isolation circuit isolates the control circuit from the external circuit by adopting an electromagnetic isolation mode and a photoelectric isolation mode, the isolation degree is high, the cost is low, and in the control signal transmission process, the control signal transmission speed is high and the control is sensitive by adopting the electromagnetic isolation mode and the photoelectric isolation mode to control the external circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit design, and in particular to a driving circuit, an isolating switch circuit and a power supply circuit. Background Art

[0002] At present, the isolating switches on the market generally use relays. Relays have problems such as long switching time and short life. Or use optocouplers to drive SCR thyristors. However, thyristors can only work in AC environments and are completely unsuitable for DC environments. Another type is a dedicated isolation driver chip that uses optical energy transmission, such as Panasonic's APV3111 and other models. However, this type of chip is slow and the driving current is too low, at the uA level, resulting in a long switching time, high cost, and limited applicable environments. Utility Model Content

[0003] In view of this, the utility model provides a driving circuit, an isolating switch circuit and a power supply circuit to solve the problems of slow switching speed and high cost of the existing isolating switch.

[0004] In a first aspect, the utility model provides a driving circuit, the driving circuit comprising: a control circuit and an isolation circuit, wherein:

[0005] A control circuit, a first end of which inputs a first control signal, a second end of which inputs a second control signal, a third end of which is connected to the first end of the isolation circuit, a fourth end of which is connected to the second end of the isolation circuit, and a fifth end of which is grounded, for providing a control signal for the isolation circuit;

[0006] An isolation circuit, whose third terminal is connected to the power supply, whose fourth terminal outputs the first drive signal, and whose fifth terminal outputs the second drive signal, is used to isolate the control circuit from the external circuit by electromagnetic isolation, or to isolate the control circuit from the external circuit by electromagnetic isolation and photoelectric isolation;

[0007] When the first control signal changes from a low level to a high level and the second control signal does not change, the fourth terminal of the isolation circuit outputs the first drive signal;

[0008] When the second control signal changes from a low level to a high level and the first control signal does not change, the fifth terminal of the isolation circuit outputs a second driving signal.

[0009] In the drive circuit provided by the utility model, the isolation circuit adopts electromagnetic isolation and photoelectric isolation to isolate the control circuit from the external circuit, with high isolation, and uses common electronic components to achieve switch isolation, without the need for expensive dedicated isolation drive chips, thereby reducing costs. During the control signal transmission process of the control circuit, electromagnetic isolation and photoelectric isolation are used to control the external circuit, and the control signal transmission speed is fast and the control is sensitive.

[0010] In an optional implementation, the control circuit includes: a first triode, a first diode, a second triode, and a second diode, wherein:

[0011] A first triode, a first end of which is connected to the first end of the isolation circuit, a control end of which inputs a first control signal, a second end of which is grounded, and when the first control signal changes from a low level to a high level, the first triode is turned on;

[0012] A first diode, a first end of which is connected to the control end of the first transistor, and a second end of which is connected to the second end of the first transistor;

[0013] A second triode, a first end of which is connected to the second end of the isolation circuit, a control end of which inputs a second control signal, a second end of which is grounded, and when the second control signal changes from a low level to a high level, the second triode is turned on;

[0014] The second diode has a first end connected to the control end of the second triode, and a second end connected to the second end of the second triode.

[0015] In the driving circuit provided by the utility model, the control circuit adopts a triode to amplify the control signal, the response speed is fast, and the diode is connected to the control end and the second end of the triode to prevent the triode from being broken down by high voltage and protect the control circuit.

[0016] In an optional implementation, the isolation circuit includes: a first isolation circuit and a second isolation circuit, wherein:

[0017] A first isolation circuit, a first end of which is connected to the power supply, a second end of which is connected to the third end of the control circuit, a third end of which outputs a second drive signal, and a fourth end of which outputs a first drive signal, and is used to isolate the control circuit from the external circuit by electromagnetic isolation;

[0018] The second isolation circuit has a first end connected to the power supply, a second end connected to the fourth end of the control circuit, a third end outputting a second drive signal, and a fourth end outputting a first drive signal, and is used to isolate the control circuit from the external circuit by electromagnetic isolation or photoelectric isolation.

[0019] The drive circuit provided by the utility model isolates the first control signal from the first drive signal, and the second control signal from the second drive signal respectively through two isolation circuits, has high isolation, reduces the influence of the waveform of the control signal on the drive signal, and improves the stability of the drive circuit.

[0020] In an optional implementation, the first isolation circuit includes: a first transformer and a third diode, wherein:

[0021] a first transformer, a first end of which is connected to the power supply, a second end of which is connected to the third end of the control circuit, a third end of which outputs a second drive signal, and a fourth end of which is connected to the anode of the third diode;

[0022] The third diode has a cathode that outputs the first driving signal.

[0023] The drive circuit provided by the utility model uses a transformer as a signal transmission medium, has high isolation, complete electrical isolation, can transmit AC signals and DC signals, has wide application and low cost.

[0024] In an optional implementation, the second isolation circuit includes: an optical coupling isolation chip and a first resistor, wherein:

[0025] An optical coupling isolation chip, wherein a first end of the optical coupling isolation chip is connected to a first end of the first resistor, a second end of the optical coupling isolation chip is connected to a fourth end of the control circuit, a third end of the optical coupling isolation chip outputs a second driving signal, and a fourth end of the optical coupling isolation chip outputs a first driving signal;

[0026] The first resistor has a second end connected to the power supply.

[0027] The drive circuit provided by the utility model utilizes an optical coupling isolation chip as a signal transmission medium, thereby effectively reducing interference and improving the reliability of the drive circuit.

[0028] In an optional implementation, the second isolation circuit includes: a second transformer and a second resistor,

[0029] a second transformer, a first end of which is connected to the first end of the second resistor, a second end of which is connected to the fourth end of the control circuit, a third end of which outputs the second drive signal, and a fourth end of which outputs the first drive signal;

[0030] The second resistor has a second end connected to the power supply.

[0031] The drive circuit provided by the utility model uses a transformer as a signal transmission medium, has high isolation, complete electrical isolation, can transmit AC signals and DC signals, has wide application and low cost.

[0032] In a second aspect, the utility model provides an isolating switch circuit, the isolating switch circuit comprising the driving circuit and the switch circuit of any one of the first aspects, wherein:

[0033] a switch circuit, a first end of which inputs a first drive signal, a second end of which inputs a second drive signal, a third end of which is connected to a first end of an external power supply, and a fourth end of which is connected to a second end of the external power supply, and is used to be turned on or off according to the first drive signal and the second drive signal;

[0034] When the switch circuit is input with the first drive signal and the second drive signal is not input, the switch circuit is turned on;

[0035] When the switch circuit is input with the second driving signal and is not input with the first driving signal, the switch circuit is turned off.

[0036] The isolating switch circuit provided by the utility model improves the isolation degree by utilizing the driving circuit of the first aspect. The switch circuit is disconnected or connected according to the input first driving signal or second driving signal, and the control mode of connection or disconnection is simple and fast.

[0037] In an optional implementation, the switch circuit includes: a first transistor and a second transistor, wherein:

[0038] A first transistor, a first end of which is connected to a first end of an external power source, a control end of which inputs a first driving signal, and a second end of which is connected to a second end of the second transistor;

[0039] The second transistor has a first end connected to the second end of the external power supply, a control end connected to the first end of the first transistor, and a second end inputting a second driving signal.

[0040] The isolating switch circuit provided by the utility model adopts two transistors to perform switching action, and can switch the switch state under power. The transistor is a semiconductor device, has no physical loss during switching action, and has a long service life.

[0041] In a third aspect, this embodiment provides a power supply circuit, the power supply circuit comprising the isolation switch circuit of any one of the second aspects, a third resistor, and a power supply, wherein:

[0042] a third resistor, a first end of which is connected to the first end of the power supply, and a second end of which is connected to the third end of the switch circuit;

[0043] a power source, a second end of which is connected to a fourth end of the switch circuit;

[0044] When the switch circuit is turned on, the power circuit is turned on;

[0045] When the switch circuit is opened, the power circuit is disconnected.

[0046] In the power supply circuit provided by the utility model, the isolating switch circuit uses simple components to achieve signal isolation and control switch, with high isolation degree and low cost. In addition, a resistor is connected in series in the power supply circuit to avoid short circuit of the external power supply, thereby improving the safety of the power supply circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 is a structural schematic diagram of a driving circuit according to an embodiment of the utility model;

[0049] Figure 2 is a schematic structural diagram of another driving circuit according to an embodiment of the utility model;

[0050] Figure 3 is a structural schematic diagram of another driving circuit according to an embodiment of the utility model;

[0051] Figure 4 It is a structural schematic diagram of an isolating switch circuit according to an embodiment of the utility model;

[0052] Figure 5 It is a structural schematic diagram of a power supply circuit according to an embodiment of the utility model;

[0053] Figure 6 It is a switch timing diagram in a power supply circuit according to an embodiment of the utility model. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0055] Common isolating switches on the market and their corresponding shortcomings are as follows:

[0056] 1. Mechanical relay: It is large in size and weight, has a slow switching speed (generally 100us~150ms), cannot be switched with power on, and has a short lifespan (generally hundreds to hundreds of millions of times). If ordinary mechanical relays are switched with power on, sparks will appear between the contacts, ablate the contacts, seriously affect the lifespan, and cannot work reliably for a long time;

[0057] 2. Solid-state relay: Generally, thyristor is used as the actuator, which can only be used in the load AC environment. Its shutdown depends on the negative half cycle of AC power, and its use environment is limited;

[0058] 3. Dedicated isolation driver chip: For example, Panasonic's APV3111 and other models use optical energy transmission to drive MOSFET or IGBT, which is a more appropriate approach. However, it is costly and slow (switching speed is 100us level). It is generally not a problem in general applications, but in ATE environments, it will become a fatal flaw and seriously affect production capacity;

[0059] 4. Photoelectric relay: For example, Panasonic AQY225, in addition to the disadvantages of dedicated isolation driver chips, it has a fatal disadvantage: it is difficult to increase the current and can only be used in very low power environments, which is very limited.

[0060] In order to overcome the above technical defects, the embodiments of the utility model provide a driving circuit, an isolation switch circuit and a power supply circuit, which isolate the switch energy through electrical isolation or photoelectric isolation to achieve the effects of fast switching speed, low cost and wide application range.

[0061] The utility model provides a driving circuit, such as Figure 1 As shown, the driving circuit includes: a control circuit 1 and an isolation circuit 2, wherein:

[0062] The control circuit 1 has a first end that inputs a first control signal, a second end that inputs a second control signal, a third end that is connected to a first end of the isolation circuit 2, a fourth end that is connected to a second end of the isolation circuit 2, and a fifth end that is grounded, and is used to provide a control signal for the isolation circuit 2.

[0063] The isolation circuit 2 has a third end connected to the power supply, a fourth end outputting a first drive signal, and a fifth end outputting a second drive signal, and is used to isolate the control circuit 1 from the external circuit by electromagnetic isolation, or to isolate the control circuit 1 from the external circuit by electromagnetic isolation and photoelectric isolation.

[0064] When the first control signal changes from a low level to a high level and the second control signal does not change, the fourth terminal of the isolation circuit 2 outputs the first drive signal. When the second control signal changes from a low level to a high level and the first control signal does not change, the fifth terminal of the isolation circuit 2 outputs the second drive signal.

[0065] Specifically, both control signals of the control circuit 1 are effective on the rising edge, that is, when the control signal changes from a low level to a high level, the control signal has a control effect on the control circuit 1, and the two control signals input to the control circuit 1 are not effective at the same time. When the switch action is not required, the first control signal and the second control signal both maintain a low level. When the first control signal has a rising edge, and the second control signal does not change or does not have a rising edge, the isolation circuit 2 outputs a first drive signal, and the first drive signal is isolated from the first control signal in an electrically isolated manner; when the second control signal has a rising edge, and the first control signal does not change or does not have a rising edge, the isolation circuit 2 outputs a second drive signal, and the second drive signal is isolated from the second control signal in an electrically isolated manner. Two drive signals are generated by two control signals. When the first drive signal is effective, the first drive signal drives the switch execution element in the subsequent circuit to turn on, so that the subsequent circuit is opened; when the second drive signal is effective, the second drive signal drives the charge of the switch execution element in the subsequent circuit to be discharged through the isolation circuit, so that the subsequent circuit is closed.

[0066] In the driving circuit provided in this embodiment, the isolation circuit 2 uses electromagnetic isolation and photoelectric isolation to isolate the control circuit 1 from the external circuit, with high isolation, and uses common electronic components to achieve switch isolation. There is no need for expensive dedicated isolation driver chips, which reduces costs. During the control signal transmission process of the control circuit 1, electromagnetic isolation and photoelectric isolation are used to control the external circuit, and the control signal transmission speed is fast and the control is sensitive.

[0067] In some optional embodiments, such as Figure 2 As shown, the control circuit 1 includes: a first triode U1, a first diode D1, a second triode U2, and a second diode D2, wherein:

[0068] The first transistor U1 has a first end connected to the first end of the isolation circuit 2, a control end thereof inputs a first control signal, and a second end thereof is grounded. When the first control signal changes from a low level to a high level, the first transistor U1 is turned on.

[0069] The first diode D1 has a first end connected to the control end of the first transistor U1 and a second end connected to the second end of the first transistor U1. Specifically, the first diode D1 is a bidirectional diode to prevent the first transistor U1 from being broken down and protect the circuit.

[0070] The second transistor U2 has a first end connected to the second end of the isolation circuit 2, a control end thereof inputs a second control signal, and a second end thereof is grounded. When the second control signal changes from a low level to a high level, the second transistor U2 is turned on.

[0071] The second diode D2 has a first end connected to the control end of the second transistor U2 and a second end connected to the second end of the second transistor U2. Specifically, the second diode D2 is a bidirectional diode to prevent the second transistor U2 from being broken down and protect the circuit.

[0072] Specifically, the two control signals of the control circuit 1 are amplified through a transistor respectively to form two control branches, that is, D1 and U1 constitute the first control branch, and D2 and U2 constitute the second control branch. In the first control branch, when the first control signal has a rising edge and the second control signal does not change, a high level appears at the control end of the first transistor U1, thereby turning on the first transistor U1, and the amplified first control signal enters the isolation circuit 2 through the first end of the first transistor U1. The second control branch is when the second control signal has a rising edge and the first control signal does not change. The working process is the same as the first control branch, and it will not be repeated here.

[0073] In the driving circuit provided in this embodiment, the control circuit 1 uses a transistor to amplify the control signal, which has a fast response speed. The diode is connected to the second and third ends of the transistor to prevent the transistor from being broken down by high voltage, thereby protecting the control circuit 1.

[0074] In some optional embodiments, such as Figure 2 As shown, the isolation circuit 2 includes: a first isolation circuit and a second isolation circuit, wherein:

[0075] The first isolation circuit has a first end connected to the power supply, a second end connected to the third end of the control circuit 1, a third end outputting a second drive signal, and a fourth end outputting a first drive signal, and is used to isolate the control circuit 1 from the external circuit by electromagnetic isolation.

[0076] The second isolation circuit has a first end connected to the power supply, a second end connected to the fourth end of the control circuit 1, a third end outputting a second drive signal, and a fourth end outputting a first drive signal, and is used to isolate the control circuit 1 from the external circuit by electromagnetic isolation or photoelectric isolation.

[0077] Specifically, the two isolation circuits are respectively connected to the two control branches of the driving circuit. When the first control signal is valid, the first isolation circuit generates a first driving signal, and isolates the first driving signal from the first control signal through electromagnetic isolation. Similarly, when the second control signal is valid, the second isolation circuit generates a second driving signal, and isolates the second driving signal from the second control signal through electromagnetic isolation or photoelectric isolation.

[0078] The driving circuit provided in this embodiment isolates the first control signal from the first driving signal, and the second control signal from the second driving signal through two isolation circuits, respectively. The isolation is high, the influence of the waveform of the control signal on the driving signal is reduced, and the stability of the driving circuit is improved.

[0079] In some optional embodiments, such as Figure 2 As shown, the first isolation circuit includes: a second transformer TR2, a third diode D3, wherein,

[0080] The second transformer TR2 has a first end connected to the power supply, a second end connected to the third end of the control circuit 1, a third end outputting a second drive signal, and a fourth end connected to the anode of the third diode D3.

[0081] The third diode D3 has a cathode that outputs the first driving signal.

[0082] Specifically, this embodiment utilizes the isolated energy transmission characteristics of the second transformer TR2. The primary of the second transformer TR2 is connected to the control circuit 1, and the secondary is connected to the external circuit. The control circuit 1 is electrically isolated from the external circuit, which can effectively block the insulation conduction of the power transmission medium, and the isolation is high. In addition, the unidirectional conductivity of the diode is used to prevent the current of the external circuit from flowing into the secondary of the transformer.

[0083] The driving circuit provided in this embodiment uses a transformer as a signal transmission medium, has high isolation, complete electrical isolation, can transmit AC signals and DC signals, has wide applications, and is low in cost.

[0084] In some optional embodiments, such as Figure 2 As shown, the second isolation circuit includes: an optical coupling isolation chip U3, a first resistor R1, wherein:

[0085] The optocoupler isolation chip U3 has a first end connected to the first end of the first resistor R1 , a second end connected to the fourth end of the control circuit 1 , a third end outputting the second driving signal, and a fourth end outputting the first driving signal.

[0086] The first resistor R1 has a second end connected to the power supply.

[0087] Specifically, optocoupler isolation can provide higher isolation voltage and higher response speed. Optionally, it can be implemented by optocoupler isolation chip U3 through photoelectric isolation, or by using a transformer for electromagnetic isolation, or by using an electronic switch to replace the optocoupler isolation chip U3. This is only used as an example, but not limited to this.

[0088] The driving circuit provided in this embodiment uses the optical coupling isolation chip U3 as a signal transmission medium, which effectively reduces interference and improves the reliability of the driving circuit.

[0089] In some optional embodiments, such as Figure 3 As shown, the second isolation circuit includes: a second transformer TR2 and a second resistor R2,

[0090] The second transformer TR2 has a first end connected to the first end of the second resistor R2, a second end connected to the fourth end of the control circuit 1, a third end outputting the second driving signal, and a fourth end outputting the first driving signal.

[0091] The second resistor R2 has a second end connected to the power supply.

[0092] Specifically, the working principle of the second transformer TR2 is the same as the working principle of the second transformer TR2, which will not be repeated here.

[0093] The driving circuit provided in this embodiment uses a transformer as a signal transmission medium, has high isolation, complete electrical isolation, can transmit AC signals and DC signals, has wide applications, and is low in cost.

[0094] The utility model provides an isolating switch circuit, such as Figure 4 As shown, the isolation switch circuit includes the drive circuit and the switch circuit 3 of any one of the above embodiments, wherein:

[0095] The switch circuit 3 has a first end that inputs a first drive signal, a second end that inputs a second drive signal, a third end that is connected to a first end of an external power supply, and a fourth end that is connected to a second end of an external power supply, and is used to be turned on or off according to the first drive signal and the second drive signal.

[0096] When the switch circuit 3 is input with the first drive signal and is not input with the second drive signal, the switch circuit 3 is turned on.

[0097] When the switch circuit 3 is input with the second driving signal and is not input with the first driving signal, the switch circuit 3 is turned off.

[0098] Specifically, the switch circuit 3 is turned on or off depending on whether the first drive signal or the second drive signal output by the isolation circuit 2 is effectively input to the switch circuit, thereby improving the isolation of the isolation switch circuit and the switching speed of the switch circuit 3 in a low-cost manner.

[0099] The isolation switch circuit provided in this embodiment improves the isolation by using the driving circuit of the previous embodiment. The switch circuit 3 is turned on or off according to the input first driving signal or second driving signal. The control method of turning on or off is simple and fast.

[0100] In some optional embodiments, such as Figure 4 As shown, the switch circuit 3 includes: a first transistor BG1 and a second transistor BG2, wherein:

[0101] The first transistor BG1 has a first end connected to a first end of an external power source, a control end thereof inputting a first driving signal, and a second end thereof connected to a second end of the second transistor BG2.

[0102] The second transistor BG2 has a first end connected to the second end of the external power supply, a control end connected to the first end of the first transistor BG1, and a second end inputting the second driving signal.

[0103] Specifically, the first transistor BG1 and the second transistor BG2 are MOSFETs or IGBTs, and the control end of the first transistor BG1 and the control end of the second transistor BG2 are simultaneously connected to the first drive signal. When the first drive signal is valid (high level), high voltages appear at the control ends of the first transistor BG1 and the second transistor BG2, and the two transistors are turned on at the same time, and the switch circuit is also turned on; the first transistor BG1 and the second transistor BG2 have parasitic diodes inside, and the second end of the first transistor BG1 and the second end of the second transistor BG2 are simultaneously connected to the second drive signal, so that the parasitic diodes inside the first transistor BG1 and the second transistor BG2 are reversely connected to avoid reverse conduction of the first transistor BG1 and the second transistor BG2. When the second drive signal is valid (high level), the charges of the first transistor BG1 and the second transistor BG2 are discharged to the optocoupler isolation chip U3 or the second transformer TR2 of the second isolation circuit through the second end, and the first transistor BG1 and the second transistor BG2 are turned off.

[0104] In addition, the utility model uses two transistors as switch actuators. The current value when turned on is determined by the rated current of the two transistors. The goal of adapting to any current or voltage value in the circuit can be achieved by selecting transistors with different rated current values ​​or connecting multiple transistors in series and parallel.

[0105] The isolation switch circuit provided in this embodiment uses two transistors to perform switching actions and can switch the switch state under power. The transistor is a semiconductor device, has no physical loss during switching actions, and has a long service life.

[0106] The utility model provides a power supply circuit, such as Figure 5 As shown, the power supply circuit includes the isolation switch circuit of any one of the previous embodiments, a third resistor R3 and a power supply DC, wherein:

[0107] A third resistor R3, a first end of which is connected to the first end of the power source DC, and a second end of which is connected to the third end of the switch circuit. When the switch circuit is turned on, the power circuit is turned on. When the switch circuit is turned off, the power circuit is turned off;

[0108] A second end of the power source DC is connected to the fourth end of the switch circuit.

[0109] Specifically, when the first control signal changes from a low level to a high level, the current flowing through the first transistor U1 will enter the primary of the transformer, and then enter the secondary of the transformer, thereby being input to the gates of the first transistor BG1 and the second transistor BG2 through the diode, turning on the two transistors (equivalent to closing the two switch actuators and opening the isolation switch circuit), so that the voltage of the external power supply is applied to both ends of the third resistor R3, the power supply circuit is turned on, and current is generated.

[0110] When the second control signal changes from a low level to a high level, the current flowing through the second transistor U2 enters the optocoupler isolation chip U3, turning on the optocoupler isolation chip U3, and the gate and source of the first transistor BG1 and the second transistor BG2 are respectively connected to the third pin and the fourth pin of the optocoupler isolation chip U3. When current flows through the first pin and the second pin of the optocoupler isolation chip U3, the third pin and the fourth pin on the other side are turned on. At this time, the charges accumulated on the gates of the first transistor BG1 and the second transistor BG2 are discharged to the sources of the first transistor BG1 and the second transistor BG2 through the path formed by the third pin and the fourth pin of the optocoupler isolation chip U3, so that the first transistor BG1 and the second transistor BG2 are no longer turned on, which is equivalent to the two switch actuators being disconnected, and the isolation switch circuit is turned off.

[0111] like Figure 6 The figure shows the switch timing diagram in the power supply circuit, where ON represents the first control signal, OFF represents the second control signal, VG represents the secondary voltage of the second transformer TR2, and IL represents the current in the power supply circuit. When ON has a rising edge, the output voltage of the second transformer TR2 charges the two transistors through the diode and turns them on. Due to the presence of the diode, both transistors are insulated gate structures, and the charge stored on the gate cannot be automatically discharged, and they will remain in the on state. Therefore, ON only needs one rising edge to change the state of the two transistors, so that the two switch actuators change from off to on and remain on. When it is necessary to turn off the isolation switch circuit, OFF inputs a positive pulse to turn on the optocoupler isolation chip U3, and the charge stored in the gates of the two transistors is discharged through the optocoupler isolation chip U3, and the two switch actuators are turned off to complete the shutdown process. After the shutdown, since there is no charge replenishment, the off state can also be maintained.

[0112] In the power supply circuit provided by the utility model, the isolating switch circuit uses simple components to achieve signal isolation and control switch, with high isolation degree and low cost. In addition, a resistor is connected in series in the power supply circuit to avoid short circuit of the external power supply, thereby improving the safety of the power supply circuit.

[0113] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A driving circuit, characterized in that: The driving circuit includes: a control circuit and an isolation circuit, wherein: a control circuit, a first end of which inputs a first control signal, a second end of which inputs a second control signal, a third end of which is connected to the first end of the isolation circuit, a fourth end of which is connected to the second end of the isolation circuit, and a fifth end of which is grounded, for providing a control signal for the isolation circuit; an isolation circuit, the third end of which is connected to the power supply, the fourth end of which outputs the first drive signal, and the fifth end of which outputs the second drive signal, and is used to isolate the control circuit from the external circuit by electromagnetic isolation, or to isolate the control circuit from the external circuit by electromagnetic isolation and photoelectric isolation; When the first control signal changes from a low level to a high level and the second control signal does not change, the fourth terminal of the isolation circuit outputs a first driving signal; When the second control signal changes from a low level to a high level and the first control signal does not change, the fifth terminal of the isolation circuit outputs a second driving signal.

2. The driving circuit according to claim 1, characterized in that: The control circuit includes: a first triode, a first diode, a second triode, and a second diode, wherein: A first transistor, a first end of which is connected to the first end of the isolation circuit, a control end of which inputs the first control signal, a second end of which is grounded, and when the first control signal changes from a low level to a high level, the first transistor is turned on; A first diode, a first end of which is connected to the control end of the first transistor, and a second end of which is connected to the second end of the first transistor; a second triode, a first end of which is connected to the second end of the isolation circuit, a control end of which inputs the second control signal, a second end of which is grounded, and when the second control signal changes from a low level to a high level, the second triode is turned on; A second diode has a first end connected to the control end of the second transistor, and a second end connected to the second end of the second transistor.

3. The driving circuit according to claim 1, characterized in that: The isolation circuit comprises: a first isolation circuit and a second isolation circuit, wherein: a first isolation circuit, wherein a first end of the isolation circuit is connected to the power supply, a second end of the isolation circuit is connected to a third end of the control circuit, a third end of the isolation circuit outputs the second drive signal, and a fourth end of the isolation circuit outputs the first drive signal, and is used to isolate the control circuit from an external circuit by electromagnetic isolation; A second isolation circuit, whose first end is connected to the power supply, whose second end is connected to the fourth end of the control circuit, whose third end outputs the second drive signal, and whose fourth end outputs the first drive signal, is used to isolate the control circuit from the external circuit by electromagnetic isolation or photoelectric isolation.

4. The driving circuit according to claim 3, characterized in that: The first isolation circuit includes: a first transformer and a third diode, wherein: a first transformer, wherein a first end of the transformer is connected to the power supply, a second end of the transformer is connected to a third end of the control circuit, a third end of the transformer outputs the second drive signal, and a fourth end of the transformer is connected to the anode of the third diode; The third diode has a cathode that outputs the first driving signal.

5. The driving circuit according to claim 3, characterized in that: The second isolation circuit includes: an optical coupling isolation chip and a first resistor, wherein: an optical coupling isolation chip, wherein a first end of the optical coupling isolation chip is connected to a first end of the first resistor, a second end of the optical coupling isolation chip is connected to a fourth end of the control circuit, a third end of the optical coupling isolation chip outputs the second driving signal, and a fourth end of the optical coupling isolation chip outputs the first driving signal; A first resistor has a second end connected to the power supply.

6. The driving circuit according to claim 3, characterized in that: The second isolation circuit includes: a second transformer and a second resistor, a second transformer, a first end of which is connected to the first end of the second resistor, a second end of which is connected to the fourth end of the control circuit, a third end of which outputs the second drive signal, and a fourth end of which outputs the first drive signal; A second resistor has a second end connected to the power supply.

7. An isolating switch circuit, characterized in that: The isolation switch circuit comprises the drive circuit and the switch circuit according to any one of claims 1 to 6, wherein: a switch circuit, a first end of which is input with the first drive signal, a second end of which is input with the second drive signal, a third end of which is connected with the first end of the external power supply, and a fourth end of which is connected with the second end of the external power supply, and is used for switching on or off according to the first drive signal and the second drive signal; When the first driving signal is input to the switch circuit and the second driving signal is not input to the switch circuit, the switch circuit is turned on; When the second driving signal is input to the switch circuit and the first driving signal is not input to the switch circuit, the switch circuit is turned off.

8. The isolating switch circuit according to claim 7, characterized in that: The switch circuit comprises: a first transistor and a second transistor, wherein: A first transistor, a first end of which is connected to the first end of the external power supply, a control end of which is input with the first driving signal, and a second end of which is connected to the second end of the second transistor; The second transistor has a first end connected to the second end of the external power supply, a control end connected to the first end of the first transistor, and a second end inputting the second driving signal.

9. A power supply circuit, characterized in that: The power supply circuit comprises the isolation switch circuit according to any one of claims 7 to 8, a third resistor, and a power supply, wherein: a third resistor, a first end of which is connected to the first end of the power supply, and a second end of which is connected to the third end of the switch circuit; a power supply, a second end of which is connected to a fourth end of the switch circuit; When the switch circuit is turned on, the power circuit is turned on; When the switch circuit is turned off, the power circuit is turned off.

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